text: Before the isotopes can be separated and a ratio can be determined, the desired component of the tissue must be isolated. Such components include collagen, carbonate and apatite. Each component requires different means of isolation, and methods must be further specialised to account for the varied levels of decay and contamination which may occur as a result of taphonomy.
  In the case of collagen, there are three main modes of isolation:
  * Decalcification of small bone chunks in a 1-5% hydrochloric acid solution. If further decayed organic matter remains, a soak in 0.1 molar sodium hydroxide may be required. The isolated collagen is then freeze dried.
  * Demineralisation of small bone chunks in sodium salt to separate collagen, which is then freeze-dried
  * Demineralisation of powdered bone in 8% hydrochloric acid, slow hydrolysis in pH 3. If required, a further soak in 0.1 molar sodium hydroxide.
  The latter is most effective in the instance of very  poorly preserved bone, although it also faces an increased risk of contamination by other organic matter. Consequently, the supposedly isolated sample should be analysed and only tested if the readings fall within an acceptable range; most mass spectrometers now include a gas analyser as well as a combustion chamber to streamline this process.